钛氢体系中氢和缺陷相互作用机制多尺度模拟研究

项目名称： 钛氢体系中氢和缺陷相互作用机制多尺度模拟研究

项目编号： No.21503201

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 胡双林

作者单位： 中国工程物理研究院核物理与化学研究所

项目金额： 21万元

中文摘要： 钛由于其优良的吸放氢性能，常用作储氢（氘，氚）的设备器件。器件的有效性、可靠性、寿命等，与存放及使用过程中氢（氘、氚）和金属相互作用的物理化学行为密切相关，因此理解氢在钛金属中的运动和演化，特别是氢与缺陷的相互作用是一个重要的研究课题。本项目将采用密度泛函理论和密度泛函紧束缚近似相结合的方法，理论研究钛氢体系中氢和缺陷的动态演化，探讨氢对材料结构以及力学、热学电学传导等性能的影响。主要研究内容包括：1）针对不同结构的钛金属，氢在其中的固溶体等，验证改进密度泛函紧束缚参数；2）利用得到的参数，研究在温度、应变等适当外部条件下，氢与材料中位错等缺陷的相互作用；3）以及这些作用对钛氢体系局域结构的影响及相应材料性能变化。通过本项目的研究，力争建立较大尺度模型的钛氢微观结构和性能的关系，并阐明此类体系性能演化的微观机制，并为相关的实验和工程应用提供一定的理解和指导。

中文关键词： 多尺度模拟；钛氢体系；缺陷；作用机制；第一性原理计算

英文摘要： Titanium is one important kind of raw materials for devices used as hydrogen (including deurerium and tritium) storage applications due to its excellent hydrogen absoption/desorption capability and kinetics. The validity, reliability, and lifetime of these devices are tightly correlated with the H(D,T) interaction with the metal matrix during device maintainence and employment. So it would be an important project to study the envolvement of hydrogen in titanium solid solutions systems, and especially the interaction between hydrogen and defects in titanium. We will apply density functional theory (DFT) and density functional tight-binding (DFTB) method, to theoretically study the static and dynamical properties of the Ti-H(D,T) systems with defects, aimed at exploring and understanding the effects of hydrogen to structural, mechanical, and thermal, electrical conduction properties of these systems. The main contents include: 1) To verify and improve the DFTB parameters based on DFT calculations on several typical structure of titanium metal and hydrogen solid solutions; 2) To study the interactions betwen hydrogen and defects (e.g. dislocations) in titanium materials with considering some external conditions, e.g. temprature, strain, etc; 3) To study the effects of enviroments to the mechanism of local Ti-H structure evolement in hydrogen absortion process, and further the related mechanical and conductive properties. Based on our study, we are trying to build relations between micro structures and macro performaces of these systems with a relative large model, to clarify the micro mechanisms of the performace envolvement of these systems, and to supply some understanding and guidance to experimental and engingeering applications.

英文关键词： multiscale simulation;titanium-hydrogen systems;defects;interaction mechanism;first-principles calculations